Retrospective Case-Control Study of Extended Birth Perineal Tears and Risk Factors

A perineal tear is a rupture of the skin or muscle between the vagina and anus (perineum). A third-degree tear is one type of extended perineal tear (EPT), and it involves the penetration of the anal sphincter muscle. Another type of EPT is a fourth-degree laceration, which penetrates deeper into the lining of the anus or rectum. The stretching of the perineum during childbirth may result in perineal trauma. Invasive surgical interventions are required for the treatment of EPTs. For this reason, the reduction of their incidence can be achieved by fully comprehending the risk aspects associated with them.

The aim of this study is to contribute to the body of knowledge by providing insight into the various risk factors that are associated with extended perineal trauma. By following this path, this study aims to contribute to and advance Saudi Arabia's development of evidence-oriented obstetric care recommendations.

The current study is a case-control study where a review of 5000 vaginal delivery records was carried out between March 1, 2018, and March 19, 2023. For the study, cases (n = 71) were female patients who had documented greater than second-degree perineal injury. The control group (n = 238) was randomly chosen from women who had vaginal delivery but with less or equal to a second-degree perineal laceration. For each patient, we reviewed medical and obstetrics records for the following characteristics: age of diagnosis, gestational age, parity, labor induction, second-stage labor duration, mode of delivery, infant birth weight, epidural use and episiotomy indication, healthcare worker (HCW) experience, and APGAR (appearance, pulse, grimace, activity, and respiration) score.

From the 5000 births analyzed, the cases were 71 patients (1.42% of 5000 births). The mean age at diagnosis in our sample was (28.05 ± 4.66 years). The study's results showed that the following variables significantly affected the occurrence of EPTs: birth weight, labor durations, parity, HCW experience, and mode of delivery. The odds for tears were 3.69 (95% CI: 0.156-0.469) higher in nulliparous patients relative to multiparous patients. Instrumental deliveries resulted in more tears than non-instrumental deliveries with an odds ratio (OR) of 5.901 (95% CI: 2.443-14.525). This study also found that prolonged second-stage labor seems to be associated with an increased risk of perineal damage. HCW experience was looked at in relation to the increased incidence of EPTs, which showed that midwives had a lower incidence rate than physicians with an OR of 2.25 (95% CI: 1.169-4.366). Epidural usage has also been significantly associated with a lesser incidence of perineal tears, which indicates that using epidural could protect against the occurrence of EPTs.

In conclusion, the occurrence of perineal lacerations could be prevented during childbirth by taking preventative measures and having more precise judgments. Epidural was a protective factor in our study against the incidence of extensive perineal tearing. Furthermore, as compared to midwives, our study showed that the majority of EPTS occurred in cases of physicians (residents/consultants). Further research, proper documentation, and the development of evidence-based guidelines are needed to improve perineal care and reduce EPT incidence.